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Study: Pine beetle outbreaks not a big factor in the ecological severity of Western wildfires

Dead and dying lodgepole pines in Frisco, Colorado.

Dead and dying lodgepole pines in Frisco, Colorado.

Study shows no clear link between beetle-kill and ecological severity of western wildfires

Staff Report

FRISCO — For all their frenzied tree-killing during the past 10 years, mountain pine beetles haven’t been a big factor in the ecological severity of wildfires in the West, a team of university scientists said this week.

Weather and topography are the main factors in determining how much damage a wildfire does to forest ecosystems, according to the researchers with the University of Wisconsin-Madison and the Washington State Department of Natural Resources.

The new study, published in the Proceedings of the National Academy of Sciences, provides some of the first rigorous field data to test whether fires that burn in areas impacted by mountain pine beetles are more ecologically severe than in those not attacked by the native bug. The study didn’t look at fire behavior, including how fast they spread or how dangerous they are to fight. Continue reading

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Forests: Spruce beetles spreading fast in southern Rockies

State report details status of insect activities

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Spruce beetles are widely active across the mountains of southern Colorado.

Staff Report

FRISCO — Windstorms, mild winters and drought are the key factors in the continued spread of spruce beetles, which have become the dominant change agent in Colorado forests the past few years.

According to the latest annual forest health report compiled by state forest experts, spruce beetles were active across 398,000 acres in 2013, affected more than triple the amount of acreage than mountain pine beetles. Continue reading

Logging no panacea for pine beetle outbreaks

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Can we log our way to forest health?

Science sometimes missing from forest management policies

By Bob Berwyn

FRISCO — While politicians and policy makers continue to conflate a number of complex forest health and wildfire issues, a new study suggests there’s little evidence supporting the idea that logging helps to control or contain the spread of tree-killing pine beetles.

Nobody disputes the need to clear trees, brush and other fuels from around homes in fire-prone forest areas, but some lawmakers who should know better have been pushing for more logging under the guise of restoring forest health and as an antidote to insect infestations.

The idea that speedy approval of logging projects could help restore forest health was also used as a basis for short-cutting environmental reviews for logging projects, possibly resulting in negative long-term environmental impacts in forests.

But forest researchers in California and Montana said there isn’t much monitoring to assess the effectiveness of logging, and that failures often aren’t reported, probably because they don’t fit the popular narrative. Continue reading

Colorado: Pine beetle epidemic wanes

Spruce beetle infestation grows in southwestern mountains

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Aerial surveys show that spruce beetles are spreading in SW Colorado, while pine beetles slow their attack in the northern and central part of the state.

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The spread of mountain pine beetles slowed to levels last seen in 2003.

By Summit Voice

SUMMIT COUNTY — Mountain pine beetle activity in Colorado dropped dramatically in 2012, to the lowest level in 10 years, according to state and federal officials who this week released the the results of their latest aerial surveys.

Mountain pine beetles are still spreading across parts of the mountains between Estes Park and Leadville, but new activity was reported on just 31,000 acres, down from 141,000 acres in 2011. Since the outbreak started in 1996, beetles killed trees across more than 3.4 million acres, but it’s important to remember that not every single tree died.

In the aftermath of the infestation, foresters are finding that pockets of younger trees survived the wave of beetles, even in the hardest-hit areas. Continue reading

Pointing the way to pine beetle control, but at what cost?

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Pine beetle-killed trees in Summit County, Colorado.

Dartmouth scientists study pine beetle population dynamics

By Summit Voice

SUMMIT COUNTY — Dartmouth scientists say they may have found a pathway to keeping pine beetles in check, showing that their populations fluctuate between extremes, with no middle ground.

“That is different from most species, such as deer, warblers and swallowtail butterflies, whose populations tend to be regular around some average abundance based on food, weather, and other external factors,” said Matt Ayres, a professor in the Department of Biological Sciences at Dartmouth and senior author on the paper. “They don’t appear and disappear in cycles. Rather, they exist in two stable equilibrium states—one of high abundance and the other of scarcity.”

Once the population pendulum swings toward the high end, it won’t quickly or easily swing back, Ayres explained.

According to the new study, forest managers might be able to keep pine beetle populations at the low end of the scale by boosting competitor and predator beetle populations — but they don’t address how that could affect the overall equilibrium of forest ecosystems, especially those where older trees need a change agent like bark beetles to spur regeneration. Continue reading

Colorado: Study shows pine beetle invasion hasn’t led to serious nitrogen pollution in forest watersheds

Nature mitigates its own impacts

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Young trees and brush are increasing their nitrogen uptake in the wake of the pine beetle infestation, helping to minimize impacts to water quality. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — Early fears that the bark beetle epidemic could degrade water quality are proving unfounded, according to CU-Boulder scientists, who said smaller trees and undergrowth that survive the epidemic have increased their uptake of nitrogen as the older trees die.

While logging or damaging storms can drive stream nitrate concentrations up by 400 percent for multiple years, the team found no significant increase in the nitrate concentrations following extensive pine beetle tree mortality in a number of Colorado study areas, according to CU-Boulder Professor William Lewis. Continue reading

Forest mortality declines across the U.S.

Pine beetles running out of food, spruce beetle infestation growing

Mountain pine beetle mortality is on the decline across the western U.S.

Spruce and fir mortality is on the increase in Colorado.

By Bob Berwyn

SUMMIT COUNTY — Tree mortality from insects and diseases has dropped dramatically in the past few years, mainly because mountain pine beetles are running out of food, according to a new report from the U.S. Forest Service.

But the next significant cycle of insect infestation has already reached epidemic proportions in the south-central Rockies, where spruce beetles are devastating stands of mature spruce trees. The spruce beetle outbreak has been especially intense in the San Juans, where the bugs have killed almost every single mature tree from the creek bottoms all the way up to high-elevation krummholz.

It will be interesting to see if the numbers go back up after this summer’s drought weakened trees across the region.

Continue reading

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